Insulator



UNITED STATES PATENT OFFICE LOUIS MCCARTHY, OF BOSTON, MASSACHUSETTS, ASSIGNOR TO CHARLES TENNANT LEE, OF SAME PLACE, AND THE GOULD & WATSON COMPANY,

OF MASSACHUSETTS.

INSULATOR.

SPECIFICATION forming part of Letters Patent No. 413,146, dated October 15, 1889.

Application filed September 2, 1889. Serial No. 322,804. (No model.)

To all whont it may concern.-

Be it known that I, LOUIS MCCARTHY, of Boston, county of Suffolk, State of Massachusetts, have invented certain new and useful Improvements in Electric Insulators, of which the following is a specification, reference being had to the drawings accompanying and forming a part hereof, in which Figure 1 is an elevation of my device, showing a wire passing through it. Fig. 2 is a longitudinal vertical section.

The object of my invention is the construction of an electric insulator of the class more particularly known as tree insulators, which are used to support or to support and guide an electric wire as it passes a tree. Such insulators require to be so constructed that they may move, as the tree sways, relatively to the wire which they support, and yet not break or fray out the covering of the wire, if it be covered. To this end they are usually provided with rolls with which the wire comes in contact. These rolls have hitherto, so far as known to me, been mounted upon a spindle or bearing of metal, and in case they were cracked or broken the insulation was liable to be interfered with. The spindles are also liable to rust or break. Rolls so mounted upon spindles are also more liable to break or crack than if they are solid and spindles are not employed. To avoid these objections and produce an efficient and durable tree-insulator is the object of my invention.

I have embodied my invention in the best form now known to me in the device shown in the accompanying drawings, and I will describe the same, using like letters of refer: ence thereto.

A is a base, which may be of any suitable shape and provided with holes, as at b, for the reception of fastening-screws. On the base and cast integral therewith, if desired, is a box D, the sides of which are cut away, as shown at h, Fig. 1, to insure plenty of room for the passage of the wire f. The ends of the box are provided with lugs or projections g,

which project through corresponding holes in the cover H and serve to hold the cover in place, the lugs 9 being provided with pins, if desired, for this purpose. The cover H may obviously be secured in place in any other convenient manner. It is preferably secured, however, so that it may readily be removed when desired.

lVit-h in the box D, I place two rolls J, the combined diameters of which are equal substantially to the length of the box, as shown. These rolls are grooved cireumferentially, as shown, the groove being of substantially the shape and size of one-half of the wire which the insulator is to support, so that between the rolls J J, when they are placed together, there is a hole large enough to receive the electric wire, as will be clear from Fig. 2. The ends of these rolls are concaved slightly, as shown at 70, so as to lessen the friction of the roll in its boX or case D.

The rolls J may be formed of any well-known insulating material, the precise character of the material employed not being essential. The rolls J are placed loosely in the case D. As the insulator is moved relatively to the wire, the rolls revolve as freely as if mounted upon spindles, while at the same time they are much less liable to break or get out of order, and there are no bearings exposed which are liable to rust or clog and endanger the insulation.

\Vhat I claim is An electric insulator comprising a box or case with a suitable base for securing it in position, the sides of said case being open for the passage of the wire, and two rolls composed of insulating material and placed loosely within said case, said rolls being grooved circumferentially to receive the wire, substantially as shown and described.

LOUIS MCCARTHY. \Vitnesses:

TH. A. MAoLEon, O. E. NoLrE. 

